Catalyst compositions useful for olefin isomerization and disproportionation and method for preparing the catalyst compositions

ABSTRACT

Catalyst composition is provided which is prepared by impregnating high surface area, high pore volume alumina with at least one magnesium compound convertible to the oxide, and, optionally, at least one alkali metal compound which is cnvertible to the oxide, and/or at least one zirconium compound convertible to the oxide, then subjecting the impregnated support to an oxygen-containing atmosphere under conditions suitable to convert at least a portion of the magnesium, alkali metal and zirconium compounds to the oxide form. The resulting catalyst is an effective double bond isomerization catalyst, and also greatly enhances the disproportionation activity of disproportionation catalysts when used in combination therewith.

This is a division of application Ser. No. 832,547, filed Feb. 24, 1986,now U.S. Pat. No. 4,684,760.

This invention relates to the catalytic conversion of olefiniccompounds. In one aspect, the invention relates to processes for thedouble bond isomerization of mono-olefins. In another aspect, theinvention relates to catalysts for the double bond isomerization ofmono-olefins. In yet another aspect, this invention relates to catalystsuseful for the disproportionation of olefins. In a further aspect, thisinvention relates to process for the disproportionation of olefins.

BACKGROUND

Double bond isomerization, i.e., the shifting of the position of adouble bond in an olefinic compound, is a well known phenomenon. Such anoperation is frequently valuable in the conversion of one olefiniccompound to one or more isomers thereof which may be less plentiful andmore valuable. Olefinic compounds as a class are useful in themselves,such as for use as monomers to produce a wide variety of polymericcompositions, or for use as building blocks to prepare other still morevaluable compounds.

A number of catalysts are known in the art to be active in double bondisomerization. However, such double bond isomerization is frequentlyaccompanied by undesirable side reactions, such as for example,cracking, dehydrogenation, polymerization, and the like.

One use to which double bond isomerization catalysts have been put is asone component of a mixed disproportionation catalyst composition. Thedisproportionation, or metathesis, of olefins is a reaction in which oneor more olefinic compounds are transformed into other olefins ofdifferent molecular weights. The addition of double bond isomerizationcatalysts thereto has been shown to increase the disproportionationactivity of the disproportionation catalyst component.

By the term "disproportionation" or "metathesis" throughout thisspecification is meant the conversion of the feed olefinic (orunsaturated) hydrocarbon to a mixture of olefinic (or unsaturated)hydrocarbons having different numbers of carbon atoms than the feedhydrocarbons. The disproportionation of an olefin with itself to producean olefin of a higher molecular weight and an olefin of a lowermolecular weight can also be referred to as self-disproportionation. Forexample, propylene can be disproportionated to produce ethylene andcis-, and trans-2-butene. Another type of disproportionation involvesthe cross-disproportionation of two different olefins to form stillother olefins. An example of the latter would be the reaction of onemolecule of 2-butene with one molecule of 3-hexene to produce twomolecules of 2-pentene.

While many catalyst compositions are known in the art for olefindisproportionation, it is a continuing objective of those of skill inthe art to provide catalyst compositions having improved productivity,i.e., increased conversion of starting material and/or increasedselectivity to the desired reaction product.

The present invention is based upon the discovery of novel double bondisomerization catalysts as well as the discovery of a way todramatically improve the activity of disproportionation catalysts.

OBJECTS OF THE INVENTION

An object of the invention, therefore, is to provide catalysts usefulfor the double bond isomerization of olefinic compounds.

It is another object of the present invention to provide a process forthe double bond isomerization of olefinic compounds whereby minimumby-product formation along with high selectivity to the double bondisomerized product is obtained.

Yet another object of the present invention is a catalyst compositionand conversion process which give improved reactant selectivity andproduct yield upon the disproportionation of olefins.

These and other objects of the present invention will become apparentfrom the disclosure and claims herein provided.

STATEMENT OF THE INVENTION

In accordance with the present invention, I have discovered that highlyactive double bond isomerization catalysts are obtained when highsurface area, high pore volume alumina is impregnated with at least onemagnesium compound, and optionally at least one compound selected fromthe group consisting of alkali metal compounds and zirconium compounds,and thereafter subjecting the impregnated alumina support to anoxygen-containing atmosphere under conditions suitable to convert atleast a portion of the magnesium, alkali metal, and zirconium compoundsto the oxide form. Catalysts produced as described herein are highlyactive for the double bond isomerization of olefinic compounds, and arealso useful components of mixed disproportionation catalyst systemswherein a disproportionation catalyst component and a double bondisomerization catalyst component are employed for olefindisproportionation.

DETAILED DESCRIPTION OF THE INVENTION

In accordnace with the present invention, a method for preparingcatalysts is provided which comprises impregnating an alumina supporthaving a surface area of at least about 200 m² /g and a pore volume ofat least 0.45 cm³ /g with about 2 up to 20 weight % of at least onemagnesium compound which is decomposable to the oxide, and, optionally,up to about 5 weight % each of at least one or both of an alkali metalcompound which is decomposable to the oxide and a zirconium compounddecomposable to the oxide, wherein each of the recited metal loadingsare based on the weight of support and calculated based on the metal.The impregnated alumina support is then subjected to an oxygencontaining atmosphere under conditions suitable to convert at least aportion of the magnesium, alkali metal, and zirconium compounds to theoxide form.

In accordance with another embodiment of the present invention, catalystcompositions prepared in accordance with the above described novelmethod are provided.

In accordance with yet another embodiment of the present invention, aprocess forthe double bond isomerization of aliphatic olefinichydrocarbon feeds is provided which comprises contacting the olefin feedunder isomerization conditions with the catalyst composition prepared asdescribed above.

In accordance with a further embodiment of the present invention, adisproportionation process is provided which comprises contacting atleast one olefin under disproportionation conditions with adisproportionation catalyst system comprising a disproportionationcatalyst and the double bond isomerization catalyst prepared asdescribed herein above.

The alumina supports contemplated for use in accordance with the presentinvention have both high surface area and high pore volume. By "highsurface area" is meant alumina having a surface area of at least about200 meters squared per gram (m² /g), as measured by mercury surface areatechniques.

By the term "high pore volume" is meant alumina having a pore volume ofat least about 0.45 cubic centimeters per gram (cm³ /g), as measured bythe mercury core volume method. Preferred supports for use in thepractice of the present invention are those having surface areas of atleast about 220 m² /g and pore volumes of at least about 0.5 cm³ /g. Ofcourse, those of skill in the art recognize that, in general, the highertha surface area, the lower the pore volume of a given support will be,and vice versa. Thus, catalyst supports having substantially highersurface areas than those specified herein will not be able tosimultaneously achieve the desired high pore volumes; and conversely,catalyst supports having substantially higher pore volumes than thosespecified herein will not be able to simultaneously achieve the desiredhigh surface areas. Therefore, the required minimum values set forthherein for surface area and pore volume indirectly place an upper limitas to how high these values may go.

In accordance with the present invention, the alumina support isimpregnated with at least one magnesium compound which is decomposableto the oxide, and optionally with one or both of at least one alkalimetal compound which is decomposable to the oxide, and at least onezirconium compound decomposable to the oxide. While those of skill inthe art can readily determine suitable quantities of each compound toemploy in the preparation of the invention catalysts, I have found thatusing quantities of each compound in the range set forth in Table Ibelow provides active catalysts.

                  TABLE I                                                         ______________________________________                                                    Metal Loadings, Wt. %*                                                        Broad  Preferred Most Preferred                                   ______________________________________                                        Mg compound   1-20     2-10      6-9                                          Alkali Metal compount                                                                       0-5      0.2-5     0.4-2.5                                      Zirconium compound                                                                          0-5      0.3-3     0.5-2                                        ______________________________________                                         *based on the weight of untreated alumina support and calculated as the       elemental metal                                                          

Suitable compounds which are convertible to the oxide form include thehalides, oxides, sulfides, sulfates, nitrates, acetates, carbonates,oxylates, and the like, and mixtures of any two or more thereof.

Exemplary magnesium compounds include magnesium nitrate, magnesiumcarbonate, magnesium oxalate, magnesium hydroxide, magnesium chloride,and the like, as well as mixtures of any two or more thereof.

Exemplary alkali metal compounds, when optionally employed, includelithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate,lithium carbonate, sodium carbonate, potassium carbonate, lithiumoxalate, sodium oxalate, potassium oxalate, lithium hydroxide, sodiumhydroxide, potassium hydroxide, lithium chloride, lithium iodide,lithium bromide, sodium chloride, sodium iodide, potassium chloride,potassium iodide, and the like, and mixtures of any two or more thereof.

Exemplary zirconium compounds, when optionally employed, includezirconium nitrate, zirconium hydroxide, zirconium chloride, and thelike, as well as mixtures of any two or more thereof.

The alumina support and compounds to be impregnated thereon can becontacted in any suitable manner. For example, the alumina support andsupport-treating reagents can be mixed in an open vessel. When thesupport-treating reagents are provided as a solution, such as forexample, an aqueous solution, once the alumina support andsupport-treating solution are mixed, then any excess liquid can bedecanted or removed by filtration. Alternatively, the technique ofincipient wetness can be employed whereby only enough liquid is employedto thoroughly wet the support, with no residual liquid. Thus, only asmuch support-treating solution is employed as the alumina support canabsorb. This can be accomplished, for example, by sprayingsupport-treating solution over a quantity of alumina which is beingtumbled in a rotating, baffled drum. Such treatment can also be carriedout by simply pouring a predetermined quanitity of support-treatingsolution over a quantity of alumina suport contained in an open vessel.Alternatively, a measured quantity of alumina support could be added toa volume of support-treating solution such that all the liquid isimbibed by the added support. Other techniques as are known to thoseskilled in the art can also be employed. For example, a quantity ofalumina support may be placed in a tubular reactor, a volume ofsupport-treating solution may be percolated therethrough, followed byfurther treatment/activation as necessary.

The conditions of alumina support/support-treating reagent contactingare not critical. Any temperature and any period of contact time issuitable. For convenience, contacting is generally carried out at aboutroom temperature, although higher or lower temperatures can be employed.When support-treating reagents are provided as an aqueous solution,contacting is preferably carried out at a temperature not exceedingabout 100° C. A time period sufficient to allow the support and reagentsto come into intimate contact is all that is necessary. Thus, thealumina support and support-treating reagents may be brought intocontact for as little time as a few seconds to several hours or more, asconvenient.

Following contact of the alumina support and support-treating reagents,any excess liquid (if solvent or diluent is employed) can be removed bysuitable means, such as, for example, decantation, filtration, or thelike. The treated support can then be dried to remove absorbed solvent.Any suitable means, as well known by those skilled in the art, may beemployed, such as for example, oven drying, passing a vigorous stream ofdry (moisture-free) gas over the treated support, and the like. Forexample, the impregnated alumina support, prepared as described hereinabove, can be dried by heating at an elevated temperature of about 200°C. or higher by passage of an inert gas such as nitrogen over theimpregnated support. This can be accomplished within the reactor or inother suitable catalyst preparation equipment.

Dried, impregnated support is then treated in the presence of anoxygen-containing gas, such as for example, air, under conditionssufficient to convert at least a portion of the magnesium and, ifemployed, the alkali metal and zirconium compounds, to the oxide form.Temperatures in the range of about 200° C. up to about 800° C. aregenerally satisfactory for such treatment. The time for subjecting theimpregnated alumina support to the oxygen-containing gas is an amount oftime sufficient to cause oxidation of at least a portion of themagnesium, alkali metal, and zirconium compounds to the oxide form.Anywhere from a few minutes to several hours is suitable. Typically,about 15 minutes up to about 20 hours of such treatment will besufficient. Preferably, for most efficient use of reaction equipment,the dried, impregnated alumina support will be subjected tooxygen-containing atmosphere for about 30 minutes up to about 6 hours.Typically, less time is required at higher temperatures, and vice versa.The resulting catalyst composition comprises 1-20 weight % magnesiumoxide, calculated as the metal and based on the weight of the support,impregnated on a high surface area, high pore volume alumina support,optionally containing up to 5 weight % of at least one alkali metaloxide and/or up to 5 weight % of zirconium oxide also impregnatedthereon.

Aliphatic mono- and polyenes having more than three carbon atoms areamenable to isomerization or disproportionation treatment employing thecatalyst of this invention, including cyclic compounds and branchedchain as well as normal chain compounds. In general, olefins suitablefor treatment in accordance with the present invention are aliphatic oralicyclic olefinic hydrocarbons having from 4 to about 30 carbon atoms,inclusive. Preferably, the practice of the isomerization embodiment ofthe present invention is carried out with a feed comprisingmono-olefinic hydrocarbons.

Representative examples of mono-olefins useful in the practice of theisomerization embodiment of the present invention include butenes,pentenes, hexenes, octenes, decenes, and the like as well as mixtures ofany two or more thereof.

In carrying out isomerization reactions with the catalyst of theinvention, suitable reaction conditions or isomerization conditions canbe used which effectively cause double bond isomerization of the olefinspresent in the feed. In general, the temperature at which isomerizationis affected with this catalyst is about 150°-600° C. Preferably thetemperature will be in the range of about 250°-500° C. Reaction pressurecan vary appreciably and can be either super- or subatmospheric.Generally, reaction pressure will not exceed about 40 atmospheres inorder to avoid condensation reactions that ultimately lead to excessivecoke formation on the catalyst. Preferably, a reaction pressure in therange of atmospheric pressure up to about 1000 psig will be employed forthe most favorable trade-off between rate of reaction, operating andequipment costs, etc.

The isomerization reaction of the present invention can be carried outin both the liquid and gaseous phase. When reaction is carried out inthe gase phase, contact time of reactants on the catalyst can beexpressed as gas hourly space velocity (GHSV) and can range betweenabout 100 to 1000. Preferably, GHSV will range between about 200 and750. When the isomerization reaction of the present invention is carriedout in the liquid phase, contact time of reactants on the catalyst canbe expressed as liquid hourly space velocity (LHSV) and can rangebetween about 0.1 and 10. Preferably LHSV will range between bout 0.5and 10.

In accordance with a specific embodiment of the present invention, thedouble bond isomerization catalyst described herein above can be admixedwith a disporportionation catalyst. The addition of the invention doublebond isomerization catalyst to a disproportionation catalyst providesincreased olefin feed conversion compared to disproportionationreactions employing disproportionation catalyst alone.

A wide variety of disproportionation catalysts can be used in thepractice of this embodiment of the present invention. Preferredcatalysts are those selected from the group consisting of:

tungsten oxide on silica,

molybdenum oxide on alumina,

molybdenum oxide on silica,

cobalt molybdate on alumina, and

rhenium oxide on alumina.

Presently preferred are those disproportionation catalyst which havebeen well characterized and are readily available, such as for example,tungsten oxide on silica support and molybdenum oxide on aluminasupport.

When preparing a mixed bed of double bond isomerization catalystcomponent and disproportionation catalyst component, particles of thetwo catalyst components having about the same particle size can beblended. Alternatively, both the double bond isomerization catalystcomponent and the disproportionation catalyst component can beintimately blended such as by grinding into a powder, the powder thenbeing formed into other shapes such as pellets, tablets, agglomerates,extrudates, and the like, such that each particle in the catalytic zonecomprises an intimate blend of the two catalyst components. As yetanother alternative, a bed of double bond isomerization catalyst canprecede the bed of disproportionation catalyst, such that the feedolefin contacts the double bond isomerization catalyst before cominginto contact with the disportionation catalyst component. Those ofskilled in the art recognize that other appropriate techniques forobtaining a composite of the two catalyst components can also be used.

The proportion of double bond isomerization component to thedisproportionation catalyst component in the composite catalyst systemcan vary widely. At least about 0.1 part by weight of the double bondisomerization catalyst component should be present for each part byweight of the disproportionation catalyst component. There is notheoretical upper limit for the amount of the double bond isomerizationcatalyst component which can be present. Preferred ratios, for ease ofcatalyst blending, are about 0.5 up to about 20 parts by weight of thedouble bond isomerization catalyst component per part by weight of thedisproportionation catalyst component. Ratios of about 2 up to about 10parts by weight of the double bond isomerization catalyst component perpart by weight of the disproportionation catalyst component areespecially preferred because excellent catalyst performance is obtainedwhen employing such ratios.

The composite catalyst systems prepared in accordance with the presentinvention are useful, for example, for the conversion of olefins via theolefin disproportionation or olefin metathesis reaction.

The disproportionation process of the present invention comprisescontacting at least one olefin selected from the group consisting ofacyclic mono- and polyenes having at least three up to 30 carbon atomsper molecule and cycloalkyl and aryl derivatives thereof; cyclic mono-and polyenes having at least four up to 30 carbon atoms per molecule andalkyl and aryl derivatives thereof; mixtures of two or more of the aboveolefins; and mixtures of ethylene with one or more of the above olefinscapable of undergoing disproportionation with catalysts preparedaccording to the invention. Where mixtures of the above olefins withethylene are subjected to disproportionation reaction conditions, it isdesirable that the molar ratio of ethylene to olefin be at least 2.Preferably, ethylene:olefin ratios of about 4:1 or higher will beemployed for good results.

Some specific examples of olefins suitable for the disproportionationreaction in accordance with this invention include propylene, 1-butene,2-butene, 1-pentene, 2-pentene, 2,4,4-trimethyl-2-pentene and2,4,4-trimethyl-1-pentene (diisobutylene isomers), 1-hexene,1,4-hexadiene, 2-heptene, 1-octene, 2,5-octadiene, 2-nonene, 1-dodecene,2-tetradecene, 1-hexadecene, 1-phenyl-2-butene, 4-octene, 3-eicosene,3-hexene, vinylcyclohexane, 1,4-pentadiene, 1,4,7-dodecatriene,2-methyl-4-octene, 4-vinylcyclohexene, 1,7-octadiene,1,5,9,13,17-octadecapentaene, 8-cyclopentyl-4,5-dimethyl-1-decene,6,6-dimethyl-1,4-octadiene, and 3-heptene, and the like, and mixtures oftwo or more thereof.

Some specific examples of cyclic olefins suitable for the reactions ofthis invention are cyclobutene, cyclopentene, cycloheptene, cyclooctene,5-n-propylcyclooctene, cyclodecene, cyclododecene,3,3,5,5-tetramethylcyclononene, 3,4,5,6,7-pentaethylcyclodecene,1,5-cyclooctadiene, 1,5,9-cyclodecatriene, 1,4,7,10-cyclododecatetraene,6-methyl-6-ethyl-1,4-cyclooctadiene and the like, and mixtures of two ormore thereof.

The reaction temperature can vary depending upon the catalyst(s) andfeed(s) employed and upon the desired reaction products. Typically thedisproportionation reaction is carried out at a temperature in the rangeof about 0 to about 600° C.; preferably for good conversion inrelatively short reaction times, temperatures of from about 20 to about500° C. are employed.

The disproportionation reaction can be carried out by contacting theolefins to be disproportionated with the catalyst in the liquid phase orthe gas phase depending on the structure and molecular weight of theolefin. Pressure during the disproportionation reaction can vary betweenwide limits. For example, pressures between 0.1 and 500 atmospheres aresuitable, although preferred pressures are between about 1 and 40atmospheres because good conversions are obtained with readily availableequipment.

If the reaction is carried out in the liquid phase, solvents or diluentsfor the reactants can be used. Aliphatic saturated hydrocarbons e.g.,pentanes, hexanes, cyclohexanes, dodecanes and aromatic hydrocarbonssuch as benzene and toluene are suitable. If the reaction is carried outin the gaseous phase, diluents such as saturated aliphatic hydrocarbons,for example, methane, ethane, and/or substantially inert gases, e.g.nitrogen, argon, can be present. Preferably, for high product yield, thedisproportionation reaction is effected in the absence of significantamounts of deactivating materials such as water and oxygen.

The contact time needed to obtain a reasonable yield ofdisproportionation products depends upon several factors such as theactivity of the catalyst, reaction temperature and pressure, as well asthe structure of the olefinically unsaturated compound(s) to bedisproportionated. The length of time during which the olefinicunsaturated compounds to be disproportionated are contacted with thecatalyst can conveniently vary between 0.1 seconds and 24 hours althoughlonger and shorter contact times can be used. Preferably, for efficientuse of reactor equipment, times of about 1 second to about 1 hour areused.

The process of the invention can be effected batchwise or continuouslywith fixed catalyst beds, slurried catalyst, fluidized beds, or by usingany other conventional contacting techniques.

The olefinic products of the invention have established utilityincluding use as precursors of polymers, e.g., as the third component ofethylene-propylene terpolymers useful as synthetic elastomers. Cleavageof the ethylenic bonds of polyolefinic products as by ozonizationproduces di- or polycarboxylic acids which are reacted with diamines,e.g., hexamethylenediamine, to form polyamides which are useful insynthetic fibers. The olefinic products are converted to secondary andtertiary alcohols as by sulfuric acid-catalyzed hydration.Alternatively, the olefinic products are converted by conventional "Oxo"processes to aldehydes which are hydrogenated when conventionalcatalysts to the corresponding alcohols. The C₁₂ - C₂₀ alcohols therebyproduced are ethoxylated as by reaction with ethylene oxide in thepresence of a basic catalyst, e.g., sodium hydroxide, to formconventional detergents and the lower molecular weight alcohols areesterified by reaction with polybasic acids, e.g., phthalic acid, toform plasticizers for polyvinyl chloride.

A further understanding of the present invention and its advantages willbe provided by reference to the following examples.

EXAMPLE I Catalyst Preparation

The impregnated, alumina-supported isomerization catalysts used in thefollowing examples were prepared by grinding the support to within therange of -20 to +40 mesh. A quantity (usually ˜25 g) of ground supportwas then mixed with a comparable quantity (usually ˜25 mL) of aqueoussolution containing the desired amount of treating components. After thesupport had soaked in the aqueous solution for about 30 minutes, thewater was removed by rotary evaporation of the slurry, and the resultingdried material subjected to calcination in a gentle air flow at about350° C. for 2-3 hours. The metals employed and loading levels forcatalysts prepared according to this procedure are summarized in TableII.

                  TABLE II*                                                       ______________________________________                                               Metal, Loading Level (wt. %)                                           Catalyst Alkaline Earth                                                                              Alkali Metal                                                                             Other                                       ______________________________________                                        A(control)                                                                             Ca,12.7       Na,0.5     None                                        B(invention)**                                                                         Mg,1.9        None       None                                        C(invention)**                                                                         Mg,3.8        None       None                                        C'(invention)                                                                          Mg,3.8        None       None                                        C"(invention)                                                                          Mg,3.8        Na,0.6     None                                        D(invention)**                                                                         Mg,3.8        Na,1.1     None                                        E(invention)**                                                                         Mg,3.8        Na,2.2     None                                        F(invention)                                                                           Mg,4.2        Na,0.5     None                                        G(invention)**                                                                         Mg,5.7        None       None                                        H(invention)                                                                           Mg,7.1        Na,0.5     None                                        I(control)***                                                                          Mg,7.1        Na,0.5     None                                        J(invention)                                                                           Mg,7.1        Na,1       None                                        K(invention)                                                                           Mg,7.1        Li,0.34    None                                        L(invention)                                                                           Mg,7.1        Li,0.34    None                                        M(invention)                                                                           Mg,7.1        K,0.8      None                                        N(invention)                                                                           Mg,8.6        Na,0.5     None                                        O(invention)                                                                           Mg,11.4       Na,0.5     None                                        P(invention)                                                                           Mg,11.4       Na,1       None                                        Q(invention)                                                                           Mg,13.3       None       None                                        R(invention)                                                                           Mg,13.3       Na,0.5     None                                        S(invention)**                                                                         Mg,3.8        None       Zr,1.4                                      ______________________________________                                         *All catalysts were prepared using a support having a surface area of 220     m.sup.2 /g and a pore volume of 0.95 cm.sup.3 /g, unless otherwise noted.     **Catalysts so designated were prepared with support having a surface are     of 260 m.sup.2 /g and a pore volume of 0.47 cm.sup.3 /g.                      ***Catalyst I was made with support having a surface area of 250 m.sup.2      /g and a pore volume of 0.4 cm.sup.3 /g.                                 

Disproportionation catalysts were prepared by spraying an aqueoussolution of ammonium metatungstate on to silica support which wascontained in a beaker fastened to a rotating table. The solution wasadded at a rate that permitted good absorption of the solution by thesilica support. The amount of tungsten employed was sufficient toproduce a catalyst having about 7.2 weight % WO₃ on SiO₂. The catalystwas dried in a moving stream of dry nitrogen, then heated at 100° C. for0.5 hour and finally at 250° C. for 2 hours. Normally, this firstcatalyst component (1.5 grams) was mixed with the isomerization catalystcomponent, (3.8 g) and about 1.2 g of α-alumina as an inert diluentbefore activation. The mixture was then heated in the presence of air at538° C. for 3-8 hours followed by heating at the same temperature in thepresence of carbon monoxide for 10-30 minutes, and finally cooled toreaction temperature ready for the introduction of reactant feed.

EXAMPLE II

Olefin Isomerization-1-Butene

Runs were made with several different catalysts to isomerize PhillipsPure Grade butene-1. About 5g of catalyst (-20+40 mesh) was placed in a1/2" i.d. stainless steel reactor and the feed passed downflow at afeedrate of about 0.60 g/min. (or a WHSV of about 7) and a pressure ofabout 400 psig. Reaction temperature, actual catalyst used to charge thereactor and product analyses are presented in Table III. Products wereanalyzed by gas liquid chromatography (GLC).

                  TABLE III                                                       ______________________________________                                                                  Product                                             Run                       Analysis, wt. %*                                    #     Catalyst  Reaction Temp., °C.                                                                  1-C.sub.4                                                                             2-C.sub.4                               ______________________________________                                        1     MgO       150           86      14                                      2     MgO       200           75      25                                      3     MgO       250           26      71                                      4     MgO       275           21      79                                      5     A         150                                                           No reaction--                                                                 6     F         275           24      76                                      7     H         150           70      30                                      8     I         150                                                           No reaction--                                                                 9     H         275           18      82                                      10    K         150           98      2                                       11    N         200           45      55                                      12    O         200           27      73                                      13    P         150           25      75                                      14    Q         150           39      61                                      15    R         170           20      80                                      16    R         200           17      83                                      ______________________________________                                         *1-C.sub.4 is 1butene                                                         2-C.sub.4 is 2butene                                                     

The results summarized in Table III indicate that magnesium on highsurface area, high pore volume alumina is an active isomerizationcatalyst (see run 14 where high conversion is obtained at temperaturesas low as 150° C.). At higher reaction temperatures and with optimalmetal loading, nearly thermodynamic isomer ratios (1-butene/2-butene)are achieved (see run 9, for example).

EXAMPLE III Olefin Isomerization--2-Butene

The procedure described in Example II was repeated, employing 2-buteneas the olefin feed instead of 1-butene. Results are summarized in TableIV.

                  TABLE IV                                                        ______________________________________                                                                  Product                                             Run                       Analysis, wt. %*                                    #     Catalyst  Reaction Temp., °C.                                                                  1-C.sub.4                                                                             2-C.sub.4                               ______________________________________                                        17    MgO       300           3       97                                      18    J         300           18      81                                      19    R         300           20      80                                      20    R         350           22      78                                      ______________________________________                                         *1-C.sub.4 is 1butene                                                         2-C.sub.4 is 2butene                                                     

These results demonstrate that invention isomerization catalyst iseffective for conversion of 2-butene to a thermodynamic mixture of 1and2-butene.

EXAMPLE IV

Disproportionation of Ethylene plus Diisobutylene

All runs were made by passing ethylene and a mixture of diisobutyleneisomers (2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene)downflow through a vertical pipe reactor (1/2 inch diameter and 20inches in length) positioned in a temperature-controlled electricfurnace. A thermocouple was positioned in the catalyst bed to monitorreaction temperature.

About 5 inches depth of alpha-alumina particles were placed at thebottom of the pipe reactor supported with a layer of glass wool. The bedof alpha-alumina particles supported an admixture of 4.3 grams (g) WO₃/SiO₂ and 10.7 g of isomerization catalyst. This was topped with anotherlayer of glass wool and the remaining reactor space filled withalpha-alumina. The catalyst was activated by heating at 538° C. inflowing air for 8 hours followed by a 30 minute treatment with flowingcarbon monoxide at 538° C.

Ethylene used in the reaction was passed through a 13X mol sieve drierand diisobutylene employed was passed over a magnesium oxide guard bed.Feed was introduced into the reactor maintained at about 373° C. and 400psig pressure. An ethylene:diisobutylene molar ratio of about 2:1 wasintroduced at a diisobutylene molar ratio of about 2:1 was introduced ata diisobutylene feed rate of about 30 weight hourly space velocity(WHSV). Product samples were collected in a high pressure syringe andwere analyzed in a Hewlett Packard Model 5840 gas chromatograph using a1/8"×20' column packed with 10% OV101 (dimethylsilicone available fromSupelco, Inc., Bellefonte, Pa.) on Chromosorb P (red diatomaceous earthavailable from Applied Science, Deerfield, Illinois). Bomb samples ofreaction off-gases were also collected and analyzed by GLC for ethyleneand hydrogen. Reaction results are summarized in Table V.

                  TABLE V                                                         ______________________________________                                                                         Gas Analysis,                                         Isomerization                                                                            Neohexene    ,%*                                          Run No.  Catalyst   Yield        C.sub.2                                                                           H.sub.2                                  ______________________________________                                        21       MgO        53           70.5                                                                              0.75                                     22       B          56           ND  ND                                       23       C          63           69.8                                                                              0.61                                     24       C'         62           ND  ND                                       25       C"         76           ND  ND                                       26       D          64           73.3                                                                              0.67                                     27       E          56           ND  ND                                       28       G          57           ND  ND                                       29       S          61           72.6                                                                              0.44                                     ______________________________________                                         *ND = not determined                                                     

The data in Table V show that mixtures of invention isomerizationcatalyst and disproportionation catalyst give enhanced product yieldsrelative to prior art disproportionation catalyst systems. In addition,the zirconium containing catlyst (catalyst S) significantly suppressesthe amount of hydrogen by-product produced in the course of the desiredconversion.

EXAMPLE V Disproportionation of Ethylene plus 2-Butene

All runs were made by passing ethylene and a mixture of cis-andtrans-2-butene downflow through a vertical pipe reactor (1/2 inchdiameter and 20 inches in length) positioned in a temperature-controlledelecric furnace. A thermocouple was positioned in the catalyst bed tomonitor reaction temperature.

About 6 inches depth of quartz chips (-9+12 mesh) were placed at thebottom of the pipe reactor supported by a layer of quartz wool. Anotherlayer of quartz wool was placed on top of the quartz chips as supportfor a combined catalyst bed comprising about 1.5 g of silica supportedWO₃ catalyst mixed with about 3.8 g of isomerization catalyst as thesecond catalyst component. This was topped with another layer of quartzwool and the remainder of the reactor filled with quartz chips. Thecombined catalyst was activated by heating at 538° C. in flowing air forthree hours, followed by about 15-minute treatment with flowing carbonmonoxide at the same temperature and finally the catalyst was cooledunder flowing nitrogen to reaction temperature.

Ethylene used in the reaction was passed through a 13X mol sieve drierand butene feedstock was percolated through 13X mol sieve, then aluminaand finally magnesium oxide prior to use. Feed introduced into thereactor was maintained at about 400 psig pressure and between about 343and 371° C. (650°-700° F). Ethylene:butene molar ratios of about 3/1 toabout 8/1 were investigated with a total feed introduction rate of about30 weight hourly space velocity (WHSV).

The hot reactor effluent was vented to a hood; periodically the totaleffluent was sampled for analysis after 5 hours on stream using amodified, heated Series A-2 Sample-Lok syringe (Dynatech PrecisionSampling Corporation). Analyses were carried out on a 1/8"x 20' OV-101column at an initial temperature of 50° C. programmed up to 200° C.Reaction results are summarized in Table VI. Values for conversion of2-butene (Conv) presented in Table VI are calculated as weight percent;selectivity to propylene was essentially quantitative in all cases.

                  TABLE VI                                                        ______________________________________                                        Run     Isomerization  Reaction                                               No.     Catalyst       Temp, °C.                                                                       Conv                                          ______________________________________                                        30      None           330      31                                            31      MgO            330      67                                            32      H              300      70                                            33      H              330      75                                            34      J              240      73                                            35      J              270      78                                            36      J              270      67                                            37      J              270      75                                            38      J              300      77                                            39      L              270      74                                            40      M              270      59                                            41      O              270      62                                            42      R              270      55                                            ______________________________________                                    

Feed conversion is improved by the use of invention isomerizationcatalyst compared to magnesium oxide in nearly all cases summarized inTable VI. Note that runs 40-42 where feed conversion is lower than incontrol run 31, the reaction temperature is 60° lower than in thecontrol run. Thus, the conversion values for runs 40-42 are still quitegood when the temperature of reaction is considered.

The examples have been provided merely to illustrate the practice of myinvention and should not be read so as to limit the scope of myinvention or the appended claims in any way. Reasonable variations andmodifications, not departing from the essence and spirit of myinvention, are contemplated to be within the scope of patent protectiondesired and sought.

I claim:
 1. A method for preparing catalyst which comprises:(a)impregnating an alumina support having a surface area of at least 200 m²/g and a pore volume of at least 0.45 cm³ /g with:1 up to 20 wt. % of atleast one magnesium compound convertible to the oxide, based on theweight of support and calculated as the metal; 0 up to 5 wt. % of atleast one alkali metal compound convertible to the oxide, based on theweight of support and calculated as the metal; and 0 up to 5 wt. % of atleast one zirconium compound convertible to the oxide, based on theweight of support and calculated as the metal; and thereafter (b)heating the alumina support impregnated in accordance with step (a) inan oxygen-containing atmosphere under conditions suitable to convert atleast a portion of said magnesium, alkali metal, and zirconium compoundsto the oxide form.
 2. A method in accordance with claim 1 wherein saidconditions suitable to convert at least a portion of said compounds tothe oxide form comprise a temperature in the range of 200 up to 800° C.for a period of time in the range of 0.5 up to 12 hours.
 3. A method inaccordance with claim 1 wherein said at least one magnesium compound ismagnesium nitrate.
 4. A method in accordance with claim 1 wherein saidat least one alkali metal compound is present in the range of about 0.2up to 5 wt. %.
 5. A method in accordance with claim 4 wherein said atleast one alkali metal compound is a compound of sodium.
 6. A method inaccordance with claim 5 wherein said compound of sodium is sodiumnitrate.
 7. A method in accordance with claim 1 wherein said at leastone zirconium compound is present in the range of about 0.3 up to 3 wt.% and said zirconium compound is zirconium nitrate.
 8. A method inaccordance with claim 1 wherein said alumina support has a surface areaof at least 220 m² /g and a pore volume of at least 0.5 cm³ /g.
 9. Acatalyst composition comprising an alumina support having a surface areaof at least 200 m² /g and a pore volume of at least 0.45 cm³ /g on whichis deposited by impregnation1 up to 20 wt. % of magnesium oxide, basedon the weight of support and calculated as the metal; 0 up to 5 wt. % ofat least one alkali metal oxide, based on the weight of support andcalculated as the metal; and 0 up to 5 wt. % of zirconium oxide, basedon the weight of support and calculated as the metal.
 10. A catalystcomposition in accordance with claim 9 wherein said at least one alkalimetal oxide is present in the range of about 0.2 up to 5 wt. %.
 11. Acatalyst in accordance with claim 10 wherein said at least one alkalimetal oxide is sodium oxide.
 12. A catalyst in accordance with claim 9wherein zirconium oxide is present in the range of about 0.3 up to 3 wt.%.
 13. A catalyst in accordance with claim 9 wherein said aluminasupport has a surface area of at least 220 m² /g and a pore volume of atleast 0.5 cm³ /g.
 14. A catalyst composition comprising(a) adisproportionation catalyst selected from the group consistingof:tungsten oxide on silica, molybdenum oxide on alumina, molybdenumoxide on silica, cobalt molybdate on alumina, and rhenium oxide onalumina; and (b) an isomerization catalyst comprising an alumina supporthaving a surface area of at least 200 m² /g and a pore volume of atleast 0.45 cm³ /g and a pore volume of at least 0.45 cm³ /g on which isdeposited by impregnation1 up to 20 wt. % of magnesium oxide, based onthe weight of support and calculated as the metal; 0 up to 5 wt. % of atleast one alkali metal oxide, based on the weight of support andcalculated as the metal; and 0 up to 5 wt. % of zirconium oxide, basedon the weight of support and calculated as the metal.
 15. A catalystcomposition in accordance with claim 14 wherein said at least one alkalimetal oxide is present in the range of about 0.2 up to 5 wt. %.
 16. Acatalyst in accordance with claim 15 wherein said at least one alkalimetal oxide is sodium oxide.
 17. A catalyst in accordance with claim 14wherein zirconium oxide is present in the range of about 0.3 up to 3 wt.%.
 18. A catalyst in accordance with claim 14 wherein said aluminasupport has a surface area of at least 220 m² /g and a pore volume of atleast 0.5 cm³ /g.
 19. A method in accordance with claim 1 wherein thestep of impregnating the alumina support is accomplished by contactingthe support consisting essentially of alumina with a solution containingthe impregnating compounds and then drying the support to remove excesssolution.
 20. A method in accordance with claim 1 wherein step a) isaccomplished by contacting said alumina support with an aqueous solutionconsisting essentially of said1 up to 20 wt. % of at least one magnesiumcompound convertible to the oxide, based on the weight of the supportand calculated as the metal, 0 up to 5 wt. % of at least one alkalimetal compound convertible to the oxide, based on the weight of thesupport and calculated as the metal, and 0 up to 5 wt. % of at least onezirconium compound convertible to the oxide, based on the weight of thesupport and calculated as the metal, in aqueous solution, and thereafterdrying said contacted support to remove excess liquid.
 21. A compositionin accordance with claim 9 wherein said support consists essentially ofalumina.
 22. A composition in accordance with claim 14 wherein saiddisproportionation catalyst and said isomerization catalyst are in theform of a physical mixture, and said support consists essentially ofalumina.